Automatic zig-zag sewing machine provided with a double needle action, needle-bar device



May 9, 1967 BUNSAKU TAKETOMI 3,313,272

AUTOMATIC ZIG-ZAG SEWING MACHINE PROVIDED WITH A DOUBLE NEEDLE ACTION, NEEDLEBAR DEVICE Filed Oct. 28, 1964 2 Sheets-Sheet 1 'F'iG.l

INVENTOR. Bun $11k Takdom i y 9, l967 BUNSAKU TAKETOMI AUTOMATIC ZIG-ZAG SEWING MACHINE PROVIDED WITH A DOUBLE NEEDLE ACTION, NEEDLE-BAR DEVICE Filed Oct. 28, 1964 2 Sheets-Sheet 2 FIG.3

FIG.4

INVENTOR. B n k Txk hm' United States Patent 3,318,272 AUTOMATIC ZIG-ZAG SEWING MACHINE PRO- VIDED WITH A DOUBLE NEEDLE ACTION, NEEDLE-BAR DEVICE Bunsaku Taketomi, 9, Z-chome, Uchiyama-cho, Chikusa-ku, Nagoya-511i, Japan Filed Oct. 28, 1964, Ser. No. 407,052 Claims priority, application Japan, Oct. 31, 1963, 38/ 8,896 3 Claims. (Cl. 112-158) This invention relates to an automatic zig-zag sewing machine provided with a double needle action, needlebar device.

While various types of zig-zag type sewing machines have been devised, they are for the most part inconvenient to use in that, in order to sew patterns, letters and the like of various configurations or to stitch button holes, it has been necessary to frequently reverse the direction of feed of the fabrics being sewn.

Accordingly it is the principal object of this invention to eliminate the above-mentioned difiiculty.

Another object of this invention is to provide a novel automatic zig-zag sewing machine provided with a double needle act-ion, needle-bar device which can sew patterns of various configurations, which are symmetrical or not symmetrical, by a single forward feed without the necessity of frequent reversal of the direction of feed of the fabric being sewn.

Briefly stated, this invention can be practiced by providing a double needle action, needle-bar device comprising a pair of vertically disposed needle-bar frames adapted to movably receive a pair of needle bars, each of said needle bars having a needle holder at its lower end so as to dispose two needles in close proximity and one of said needle bars being given a vertical reciprocating motion, means to pivotally suspend said needle-bar frames substantially in parallel relation, means to interconnect said needle bars to cause them to move in unison and in synchronism in the vertical direction, a pair of cams disposed between said needle-bar frames to cooperate with a different one of said needle-bar frames, means to bias said needle-bar frames against respective cooperating cams, a zig-zag motion inducing mechanism to impart to said cams independent oscillatory motions. Thus, as the pair of needles are given independent oscillatory motions, it is able to provide patterns, letters and the like of any sy-mmetrical or asymmetrical configuration without the necessity of reversing the direction of feed.

Other objects and advantageswill be apparent from the following detailed description when considered in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevation of a double needle action, needle-bar device embodying this invention;

FIG. 2 is :a sectional view taken along the plane indicated by line II-II in FIG. 1;

FIG. 3 is a perspective view of the needle-bar device constructed according to the principle of this invention; and

FIG. 4 is a planar view showing some examples of stitching patterns that can be made with a sewing machine of this invention.

Referring now to the accompanying drawing, in FIG. 1 there are illustrated only essential components which are necessary for an understanding of the invention. A pair of spaced needle-bar frames 5 and 5' comprising reinforcing ribs 4 and 4, respectively, and having a letter L shaped cross section are pivotally suspended at their upper ends by pins 2 and 2', respectively. A pair of vertical needle bars 3 and 3' are journalled in upper bearings '--6 and lower bearings 6"--6" supported by the ice needle-bar frames 5 and 5, the lower bearings 6"6" being slidably received in a horizontal slot 24 formed at the left lower portion of the head of the sewing machine, as best shown in FIG. 3. Thus, it will be seen that the pair of needle-bar frames 5 and 5 are pivoted around pivot pins 2 and 2 so that their lower ends can oscillate freely in the slot 24.

To the right needle bar 3, there is secured a boss 28 which is connected to a pin 29 of a crank rod to provide vertical reciprocation motions. Although the detail of the boss is not shown, it is constructed similar to a universal joint so 'as to follow the inclination of the needle bar due to its horizontal oscillation, as is well known in the art. A connecting member 9 is secured by screws to the front surface of the boss 29' to extend toward the left. The left hand end of the connecting member 9 is provided with a horizontal slot 10 adapted to slidably receive .a rectangular block 7 projecting outwardly from a stopper 8 secured to the lefthand needle bar 3. Thus, as the left and right needle bars 3 and 3' are connected together through the connecting member 9, these needle bars are caused to be moved simultaneously in the vertical direction. As shown in FIG. 3 a transverse bearing bushing 23 is provided between the needle bars having a perforation to journal a horizontal, central shaft 19' provided with a semicircular cam 19 on its fore end. A sleeve 20' is inserted in the fore end of the bearing bush ing having a second semicircular cam 20 at its fore end. Thus, the dual shafts 19 and 20 are received in the bore of the bearing bushing 23. Links 16 and 17' are respectively connected to the outer ends of arms 16 and '17" which are respectively secured to the rear ends of the central shaft 19' and the sleeve 20, the opposite ends of the links 16' and 17 being connected to a pair of disc cams 15 and 15' of a well known zig-zag motion inducing mechanism 13, 14, 15, 15, 16, 17 and 18. Thus when a worm 13 is rotated, the cam '19 at the fore end of the central shaft 19 and the cam 20 at the fore end of the sleeve shaft 20 are caused to oscillate, so that the lower portions 6"6" of the needle-bar frames 5 and 5 which are urged against the cams by a spring 22 are caused to undergo independent oscillations of any desired amplitudes. Thus, the needle-bar frames 5 and 5' can oscillate independently. As a result the amplitudes of oscillations of the left and right needles 27 and 27' which are secured to needle holders 25 and 25', respectively, at the lower ends of the needle bars can be varied independently within pitch ranges A and B on the opposite sidesof a center line N. Thus, by employing two zig-zag cams 15 and 15' of appropriate design, it is possible to provide patterns of any configuration which are symmetrical or not symmetrical with respect to the center line N, as shown in FIG. 4.

As can be seen from the foregoing description, since in accordance with this invention independent oscillations are imparted to the left and right needle bars by utilizing two zig-zag motion inducing cams, it is possible to sew with high efficiency various symmetrical or asymmetrical patterns in addition to those illustrated in FIG. 4 and to stitch button holes during a single forward sewing run, which is very advantageous and convenient for the operator.

It is to be understood that the above-described arrangement is simply illustrative of the application of the principle of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof as set forth in the appended claims.

What I claim is:

1. An automatic zig-zag sewing machine provided With a double needle action, needle-bar device comprising .a pair of needle-bar frames adapted to support needle bars, each of said needle bars having a needle holder at its lower end so as to dispose two needles in close proximity, means to pivotally suspend said needle-bar frames substantially in parallel relation, means to interconnect said needle bars to cause them to move in unison and in synchronism in the vertical direction, a pair of cams each cooperating with a different one of said needle-bar frames, means to bias said needle-bar frames against respective cooperating cams, and a zig-zag motion inducing mechanism to impart to said cams independent oscillatory motions thereby to cause symmetrical or asymmetrical patterns to be sewn by a single forward sewing run.

2. The sewing machine according to claim 1 wherein said needle bars are journalled by upper and lower bearings secured to said needle-bar frames, and said means interconnecting said needle bars comprises a horizontal connecting member fixedly secured at one end to one of said needle bars which is caused to undergo a vertical reciprocating motion by a crank, the other end of said connecting member being provided with a horizontal slot adapted to slidably receive a projection secured to the other needle bar.

3. The sewing machine according to claim 1 wherein said cams are secured to the fore ends of a horizontal, central shaft and a sleeve, respectively, said central shaft and sleeve are concentrically extending through a transverse bearing bushing situated between said needle-bar frames, and said zig-zag motion inducing mechanism is connected to the rear ends of said central shaft and sleeve.

References Cited by the Examiner UNITED STATES PATENTS 7/1921 Crozet 112158 7/1943 Hale "112158 

1. AN AUTOMATIC ZIG-ZAG SEWING MACHINE PROVIDED WITH A DOUBLE NEEDLE ACTION, NEEDLE-BAR DEVICE COMPRISING A PAIR OF NEEDLE-BAR FRAMES ADAPTED TO SUPPORT NEEDLE BARS, EACH OF SAID NEEDLE BARS HAVING A NEEDLE HOLDER AT ITS LOWER END SO AS TO DISPOSE TWO NEEDLES IN CLOSE PROXIMITY, MEANS TO PIVOTALLY SUSPEND SAID NEEDLE-BAR FRAMES SUBSTANTIALLY IN PARALLEL RELATION, MEANS TO INTERCONNECT SAID NEEDLE BARS TO CAUSE THEM TO MOVE IN UNISON AND IN SYNCHRONISM IN THE VERTICAL DIRECTION, A PAIR OF CAMS EACH COOPERATING WITH A DIFFERENT ONE OF SAID NEEDLE-BAR FRAMES, MEANS TO BIAS SAID NEEDLE-BAR FRAMES AGAINST RESPECTIVE COOPERATING CAMS, AND A ZIG-ZAG MOTION INDUCING MECHANISM TO IMPART TO SAID CAMS INDEPENDENT OSCILLATORY MOTIONS THEREBY TO CAUSE SYMMETRICAL OR ASYMMETRICAL PATTERNS TO BE SEWN BY A SINGLE FORWARD SEWING RUN. 